File Input and Output Flashcards

Which io class should you use to work with in-memory text streams?

Answer: io.StringIO

io.StringIO provides an in-memory stream for text, implementing the same interface as a regular text file.

What does pathlib.Path.write_text(data) do if the file already exists?

Answer: Overwrites the file with the new data

Path.write_text() opens the file in 'w' mode and overwrites any existing content with the provided text.

Which method of pathlib.Path lists all immediate children of a directory?

Answer: Path.iterdir()

Path.iterdir() yields Path objects for all entries (files and directories) directly inside the directory.

What does open(file, buffering=0) mean?

Answer: Disable buffering (only valid in binary mode)

Setting buffering=0 disables buffering; this is only permitted in binary mode and causes each read/write to go directly to the OS.

What does shutil.copy2(src, dst) preserve that shutil.copy(src, dst) does not?

Answer: File metadata (timestamps)

shutil.copy2() copies content and permissions like copy(), but also preserves the file's metadata such as modification timestamps.

When iterating over a file object line by line with 'for line in file:', what is included in each line?

Answer: The line with its trailing newline character

When iterating a file, each yielded string includes the trailing newline '\n', which you must strip manually if not needed.

What is the purpose of the errors parameter in open()?

Answer: Specifies how encoding/decoding errors are handled

The errors parameter (e.g., 'ignore', 'replace', 'strict') defines what happens when a character cannot be encoded or decoded.